Conventional wrenches are provided with a direction switch including two direction control members that are actuated simultaneously. There are many prior arts approved, such as U.S. Pat. No. 6,918,477, in which both sides of a driving portion of a wrench are each equipped with a direction control member respectively, and a coupling means is provided between the direction control members to allow simultaneous actuation thereof. The structure of the coupling means has many embodiments, in which the two direction control members are equipped with structures that are operatively connected with each other, through a penetrating bore to connect into a structure of simultaneous actuation on the wrench. Such structures have shortcomings, which are:
1. The structured of the direction control members are too complicated to be formed easily: because the direction control members must have the structures matched with each other, therefore, the structures of the direction control members are too complicated, which are not only hard to be formed but also high cost of manufacture, it is necessary to be improved.
2. Limited stability of connection: because the direction control member s are formed into a structure of connection with each other, the strength of the connection is extremely limited, there is the shortcoming of coming off after an impact, therefore, the whole direction control structure is unable to be operated efficiently, which will affect the lifetime of the whole structure.
This case has another embodiments, in which after the connection of the two direction control members, which are screwed together by a screw. However the structure of the screw connection needs to dispose a through hole and an inner-threaded hole on the direction control members respectively, so that the screw can pass through one direction control member and fasten the other direction control member together, so as to connect the two direction control members into a structure of simultaneous actuation. Such structure still has shortcomings, which are:
1. The structure and assembly are still too complicated: after the two direction control members are connected together, which need to be screwed, that has not only the forementioned shortcomings but also the complication of assembly, therefore, which consumes unnecessary cost of labor and assembly structure, it needs to be improved.
2. The screw connection is unstable: because the place of using the wrench might have not only high frequency of shaking but also greasiness, the screw is easy to loosen due to the shaking, and furthermore the location of the screw is easy to cause unnecessary contamination due to the greasiness, so that while the direction control members are damaged, which are hard to exchange efficiently and instantly, it is inconvenient to use.